President Obama heads to Canada today on his first diplomatic trip abroad. Canada's Prime Minister Stephen Harper has indicated he wants to use the trip as an opportunity to talk to President Obama about Alberta's tar sands oil- the dirtiest oil on Earth.

The Canadian press has reported that the country will seek a U.S.-Canada climate agreement that shelters tar sands oil from regulation. During his visit, Obama will likely face immense pressure to offer special treatment for this dirty, destructive oil.

Tar sands oil is the fastest growing source of global warming emissions in Canada. Its production creates three times the amount of greenhouse gases as conventional oil. In Alberta, tar sands drilling, pipelines, roads and surface mining have obliterated a large swath of what was once strikingly beautiful boreal forest. Its toxic tailing ponds span nearly 20 square miles of forest and bogs.

Last year, a flock of 500 ducks was found dead in one of the nasty ponds. Worse, tar sands have been linked to high rates of rare cancers in nearby indigenous communities. But the destruction doesn't stop at the border.

In the United States, a vast web of pipelines and refineries designed to transport the oil from Canada threatens communities throughout the Midwest with air pollution, water degradation and unchecked industrial development.

While energy security for both Canadians and Americans is essential, we also need green jobs, healthy communities and swift and decisive action on climate change. The integrity of any kind of North American climate agreement would be compromised should it somehow give a free pass to the production of high carbon oil from the tar sands.

Emissions cuts in any agreement will need to be deep for all types of dirty fuels. Placing an extra burden on some sectors in order to allow emissions from tar sands oil to grow, or even to stay constant, is not an acceptable solution. Instead, our countries must work together toward greater conservation, improved energy efficiency measures and green job development.

The most exciting conversation Obama and Harper can have is one about how energy trade between our two countries can shift to renewable energy and technologies for energy efficiency. Both the United States and Canada have a tremendous supply of clean, renewable energy sources - sources that won't contribute to global warming, harm public health or destroy the environment. An investment in clean energy would boost our economies and create much-needed lasting, sustainable jobs in both of our countries.

The good news is that Obama clearly understands the benefits of a low-carbon economy. He's made it a key element of his economic recovery plan. The president has already proven he is serious about clean energy. Alberta tar sands oil, the dirtiest oil on Earth, clearly has no place in his vision.